The present invention relates generally to recording devices which realizes recording by adhering a recording material (liquid such as ink or particles/powder such as toner) to a recorded medium (for example, such as a printing paper or OHP film), and more particularly to a surface treatment of a feed belt which carries a recorded medium in the recording device.
The present invention is suitable for inkjet printers and electrophotographic (such as laser) recording devices that may provide high-speed and high-quality printing. The xe2x80x9cinkjet printerxe2x80x9d as used herein, means a non-impact printer (which does not use a ink ribbon and) that jets an ink drop from a nozzle onto a printing paper. The xe2x80x9celectrophotographic recording devicexe2x80x9d, as used herein, means a non-impact printer that realizes recording by adhering toner to a printing paper.
Inkjet printers, compatible with both monochromatic and multicolor printings and sold at a reasonable price, have become one of the most attractive small printers, superseding other types of printers, such as serial printers which print each letter, line printers which print each line, and page printers which print each page.
The inkjet printer is expected to provide a high-speed printing and high-quality image formation. These purposes necessitate the high-speed feeding and prevention of bending of a printing paper, in addition to control over the ink-drop amount and concentration ejected from a print head (inkjet head), and the increased number of nozzles in the head for high resolution. For example, the roller feeding at both ends of a printing paper would often slightly distort the paper due to vibration during the feeding and a difference in friction force between each roller and the paper. The slack paper would dislocate landing points of ink drops and thereby deteriorate the image quality, as well as besmear the paper surface with ink when contacting the nozzle. In particular, the increased number of nozzles makes large the head, and increasingly narrow an interval (or gap) between the head and printing paper near the nozzle, leading to the above disadvantages.
Accordingly, in place of using a roller to feed a printing paper, an absorptive belt that electrostatically absorbs one side of and feeds a printing paper using the triboelectric series has been proposed so as to feed the printing paper at a high speed while preventing the paper from bending. The xe2x80x9ctriboelectric seriesxe2x80x9d, as used herein, is an arrangement of (electrostatically charged things or) things which store electrostatic charges generated along with a dynamic action such as a contact or separation between things, as seen in two things rubbed together, from those tending to get charged into plus to those tending to get charged into minus. The triboelectric series may indicate which of two things rubbed together has the plus or the minus polarity, and employ the work function (eV) for quantitative representation.
Mechanically strong and heatproof materials, such as polyethylene terephthalate (PET), polyimide, polyamide, poly vinylidene fluoride (PVDF) etc., have been proposed for a feed belt. Among them, part of PVDF has been reduced to practice as absorptive belt materials. In the triboelectric series, PVDF tends to get charged into the minus side relative to a printing paper (for example, a regular paper made of cellulose as a basic component) and the printing paper tends to get charged into the plus side. Therefore, when both members are charged properly, the feed belt serves to absorb the paper.
Even an ink drop used tends to get charged into the plus or minus polarity. Only considering the electrostatic absorption matching between a printing paper and feed belt might equalize a polarity of an ink drop with that of a printing paper, and cause an electric reaction between each other. Then, a flying ink drop subject to the electrostatic force would yield a dislocated landing point, and deteriorate the image quality. Therefore, the instant inventors have discovered that it is also necessary to consider the triboelectric series of an ink drop in addition to those of a printing paper and feed belt for both high-speed feeding and high-quality recording. For example, when an absorptive belt is made of PVDF, the printing paper will get charged into plus at its belt side and minus at its ink side (opposite side to the belt side). As a result, the ink drop charged into the minus side would react on the surface of the printing paper.
In particular, this reaction will dramatically deteriorate the image quality in such a recording part as an inkjet or a toner jet printer which adheres a recording material to a recorded medium spaced apart from the head.
The instant inventors have also discovered that a successful consecutive use of a feed belt would require the feed belt to be made of a material having the proper mechanical property such as a good mechanical strength, less distortion, and easy to keep clean. Nevertheless, those material which meet this mechanical property requirement do not always satisfy the above triboelectric relationship requirement, and it is not easy to elect a material which meet these two requirements.
Moreover, even a feed belt that meets the mechanical property and triboelectric relationship requirements might provide a week absorptive force insufficient to feed a recorded medium at a high speed. Thus, in some cases, in addition to the above two requirements, it is also necessary to select a material which may make large the electrostatic absorptive force between the feed belt and recorded medium. As a result, a proper selection would become increasingly difficult.
Therefore, it is an exemplified general object of the present invention to provide a novel and useful recording device and method, and feeder in which the above disadvantages are eliminated.
Another exemplified and more specific object of the present invention is to provide a recording device and method, and feeder each having a good mechanical property, such as an endurance, enough to realize a high-speed and high-quality recording.
In order to achieve the above objects, a recording device of the present invention comprises a recording part which adheres a recording material to a recorded medium, a feed belt which may electrostatically absorb and feed the recorded medium, and a drive part which drives the feed belt so as to feed the recorded medium, wherein in a triboelectric series the feed belt tends to get charged into a side of a first polarity selected from plus and minus relative to the recorded medium, and the recording material tends to get charged into a side of a second polarity opposite to the first polarity. According to this recording device, when the feed belt is charged into a plus side relative to the recorded medium, a surface of the recorded medium opposite to the feed belt gets charged into a minus side and a surface of the recorded medium at the side of the recording material gets charged into a plus side, getting along with the recording material which tends to get charged into a minus side. Inversely, when the feed belt is charged into a minus side relative to the recorded medium, a surface of the recorded medium opposite to the feed belt gets charged into a plus side and a surface of the recorded medium at the side of the recording material gets charged into a minus side, getting along with the recording material which tends to get charged into a plus side. At all events, the feed belt and recorded medium get charged into opposite polarities and absorb each other electrostatically, while the recorded medium and recording material may become in opposite polarities preventing a reaction.
A recording device of the present invention comprises a recording part which adheres a recording material to a recorded medium, an absorptive part which may electrostatically absorb the recorded medium, a feed belt connected to the absorptive part, the feed belt feeding the recorded medium via the absorptive part, and a drive part which drives the feed belt, wherein in a triboelectric series the absorptive part tends to get charged into a side of a first polarity selected from plus and minus relative to the recorded medium, and the recording material tends to get charged into a side of a second polarity opposite to the first polarity. According to this recording device, when the absorptive part is charged into a plus side relative to the recorded medium, a surface of the recorded medium opposite to the absorptive part gets charged into a minus side and a surface of the recorded medium at the side of the recording material gets charged into a plus side, getting along with the recording material which tends to get charged into a minus side. Inversely, when the absorptive part is charged into a minus side relative to the recorded medium, a surface of the recorded medium opposite to the absorptive part gets charged into a plus side and a surface of the recorded medium at the side of the recording material gets charged into a minus side, getting along with the recording material which tends to get charged into a plus side. At all events, the absorptive part and recorded medium get charged into opposite polarities and absorb each other electrostatically, while the recorded medium and recording material may become in opposite polarities preventing a reaction.
A recording method of the present invention comprises the steps of forming an absorptive part on a substrate of a feed belt which may feed a recorded medium by a surface treatment of the substrate so that the absorptive part tends to get charged, in a triboelectric series, into a side of a first polarity selected from plus and minus relative to the recorded medium and relative to the substrate, feeding the recorded medium by driving the feed belt while electrostatically absorbing the recorded medium onto the absorptive part, and adhering to the recorded medium a recording material which tends to get charged into a side of a second polarity opposite to the first polarity. This recording method thus forms the absorptive part by a surface treatment of the substrate of the feed belt. Where a material having a good mechanical property is selected for the substrate of the feed belt, the surface treatment may conveniently control a change of the triboelectric series. The surface treatment may enhance the absorption between the recorded medium and absorptive part using the triboelectric series.
A feeder of the present invention comprises a feed belt which may electrostatically absorb and feed a paper-like member, and a drive part which drives the feed belt so as to feed the paper-like member, wherein the feed belt includes a substrate, and an absorptive part which is formed by a surface treatment of the substrate and may electrostatically absorb the paper-like member, and wherein in a triboelectric series the paper-like member tends to get charged into a side of a first polarity selected from plus and minus relative to the absorptive part and the substrate tends to get charged into the side of the first polarity relative to the absorptive part. According to the feeder, where a material having a good mechanical property is selected for the substrate of the feed belt, the surface treatment may conveniently control a change of the triboelectric series. The surface treatment may enhance the absorption between the paper-like member and absorptive part using the triboelectric series.
Other objects and further features of the present invention will become readily apparent from the following description of the embodiments with reference to accompanying drawings.